[APM][Spans] Determine APM span count for contract

[robrap]

Acceptance Criteria:

• Ensure DD has good numbers for APM spans. Not too high, not too low. :)

Implementation notes:

• Ensure spans in DD for each service.
  • Why do services (e.g. edxapp-lms edge) not have enough indexed spans?
• For missing services, may need to estimate missing spans. See original NR data spreadsheet sent to DD.
• Celery instrumentation (and spans) task: [APM][Spans] Instrument edxapp celery workers in Datadog #584
• Kafka instrumentation and spans. (Not tasked separately at this time. Celery notes may help).
• Probably need a fix to tracing errors in this ticket: [APM][Spans] Resolve APM span issue seen in excessive logs #594

[robrap]

Marking as Done.